Plug-in Hybrid electric Vehicles Emit Almost as Much as Petrol Vehicles, Study Reveals

Plug-in hybrid electric vehicles release almost 5x more planet-heating pollution than official figures indicate, as per a new report.

Widening Discrepancy In Lab and Real-World Emissions

Statistics shows that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research conducted by a non-profit organization. That contrasts sharply with laboratory tests, which suggested a 75% reduction in emissions.

Researchers examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are falling,” stated a lead analyst involved in the report. “This discrepancy is widening and poses a significant issue. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to overall mileage. The team determined that only 27% of travel was done in electric mode, while official estimates assumed over four-fifths.

Additionally, when operating in EV mode, pollution amounts were significantly higher than lab projections. This happened because EV motors were not strong sufficient to operate independently, resulting to combustion motors using fossil fuels for almost one-third of the travel covered in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output enabled four large automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 more per year in operating costs than would be assumed under laboratory tests.

“The bold statements that automakers often promote about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have recently been brought back into policy debates as automakers have lobbied the EU to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive industry and resistance from member states with large car manufacturing.

Some senior officials have suggested plug-in hybrids as a potential “compromise” option to include in the legislation.

One external energy economics specialist, who was not involved with the study, called the analysis a “highly valuable contribution” after a long period in which segments of the automotive sector argued there was insufficient data to properly assess actual emissions.

“These findings show, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or diesel vehicles,” they stated. “Any policy adjustments regarding PHEVs should be implemented with extreme care and in the light of this evidence.”